Boxing’s combatants are so often molded by poverty, struggle, and a penchant for vice, it’s hard for a single story to float above a canvas of so many hard-luck tales. But once every generation or so, a fighter’s tale — both inside and outside the ring — becomes transcendent.

Manny Pacquiao has been such a boxer. But as he prepares to face rival Juan Manuel Marquez a fourth time on Saturday night, in Las Vegas, the boxing world wonders aloud: can Manny Pacquiao still throw punches like Manny Pacquiao?

The tale is now familiar: while growing up near General Santos City, Pacquiao hawked sugar doughnuts and cigarettes. He pinched what few pesos he made so his mother could buy more of the soupy rice porridge they survived on. He protected his small stake in the world with his fists.

At 16, he lied; too young to fight on a nationally televised boxing program, he told the producers he was old enough to turn pro. He was too skinny so he stashed weights in his pockets to make the 105 pound limit. He won his January 1995 debut on points. It was the first of many victories.

In 2001, he took an injured Enrique Sanchez’s spot in a bout for Lehlohonolo Ledwaba’s super bantamweight title with only two weeks to prepare for the fight. Pacquiao overwhelmed the South African champion. That January night was the start of a familiar pattern. By 2008, when Pacquiao defeated Juan Manuel Marquez in the pair’s second contest — one many boxing observers thought should have went the other way — he truly arrived.

Then, he kept rising. Over his next four fights, Pacquiao mauled David Diaz, Oscar De La Hoya, Ricky Hatton, and Miguel Cotto. With 8 seconds left in the second round against Hatton, Pacquiao looped his left hand. He had driven it, like a javelin, through the Brit’s right cheek.

Despite swelling expectations, Pacquiao answered every bell. Pacquiao became ubiquitous in the Philippines, the omnipresent and omnipotent native son. He remains a sainted champion to a nation.

Still, something changed. Pacquiao beat his next three (inferior) opponents, but his untamed fury slipped. The inevitable knockouts everyone expected never came. Pacquiao rested and measured his output. He picked spots; before, his persistence ground the other man into a bloodied rind.

And then, on November 12, 2011, Juan Manuel Marquez first cracked the Pacquiao mythos. Against Marquez, the failures came quickly and rhythmically. It was not the Filipino’s left but the older fighter’s right that did the staggering, routinely catching Pacquiao’s chin. Marquez weaved under Pacquiao’s right hooks, and spun away from the potentially lethal power shots. Abandoning reason for madness, two judges mucked up the result and gifted Pacquiao with a majority decision win. But the damage was done.

While he did perform better in his truly absurd loss to Timothy Bradley, a poll of boxing writers, trainers, and fighters by The Ring Magazine shows Pacquiao is no longer the undisputed champion of media consensus. ESPN.com’s boxing writers — Dan Rafael, Kiernan Mulvaney, and Bernardo Pilatti — all predict a Marquez win on the scorecards. Pacquiao is still favored in the soon-to-be-tetrology but the questions are more amplified than ever before. Some seem primed to turn a potential Pacquiao defeat into a referendum on whether he should retire. But even a decisive win over his chief rival won’t restore the fable. Once a legend loses some of its luster, it’s gone for good.